The perioral muscle continuum affects premaxillary development in Wistar rats

Area of Science:

• Craniofacial development
• Skeletal biology
• Oral and maxillofacial surgery

Background:

• Craniofacial deformities stem from soft tissue and skeletal abnormalities.
• Muscle activity plays a vital role in facial bone growth, influenced by congenital and iatrogenic factors.
• Limited research exists on the impact of perioral muscle continuity on maxillary development.

Purpose of the Study:

• To investigate the effects of perioral muscle continuity disruption on maxillary development.
• To understand the role of muscle function and attachment in premaxillary growth.

Main Methods:

• Mimic perioral muscle surgeries (incision, muscle stripping, periosteal stripping) were performed on 3-day-old Wistar rats.
• Groups included control, unilateral perioral muscle incision (MI), muscle incision with muscle stripping (MIMS), and muscle incision with periosteal stripping (MIPS).
• Micro-CT scans and hematoxylin-eosin staining were used for analysis after six weeks.

Main Results:

• All surgical groups exhibited significant premaxillary developmental defects on the affected side compared to controls.
• Premaxillary width and length were reduced on the affected side, especially in MIMS and MIPS groups.
• Significant differences in the premaxillary length ratio (affected vs. unaffected side) were observed between MI and MIMS groups.

Conclusions:

• Complete perioral muscle continuity with intact muscle attachment is essential for driving premaxillary development.
• Disruption of muscle continuity and periosteal integrity negatively impacts maxillary growth.
• Findings highlight the mechanical influence of perioral muscles on craniofacial skeletal development.